Tuesday, June 28, 2011
I Saw 2011 MD (and I've Got The Pictures To Prove It)
I managed to successfully image the speeding rock 2011 MD which came within the orbit of geostationary satellites (12,000 kilometers from Earth) in the early hours of this morning. WOOT!
Left image, 2011 MD at 22:46 (local time), when it was moving at 408.78"/min (120 sec exposure with GRAS-12). Right Image, 2011 MD at 23:30 local time, when it was moving at 611.15"/min (120 sec exposure with GRAS-12). The asteroid seems to fade out but its brightness fluctuated probably due to rotation.
Well, some of you might be saying, "so what, all you had to do was put coordinates into a robot telescope, where's the challenge in that?" and there is a degree of truth in that. Mind you, given my inherent fumble-fingeredness, even that can be a challenge. The last time I tried to image a rapidly moving asteroid I neglected to correct for daylight saving time and imaged a patch of empty space. Repeatedly.
But in this case it was more complicated. When I put the MPEC elements into my favourite planetarium programs, SkyMap and Stellarium, the tracks I got back were just rubbish. Peter Lake had actually got some images, and I asked him for help. It turns out that the MPEC generate their ephemeris to a standard epoch, sufficiently far into the future that it messes up with plotting the asteroids track in most planetarium programs (it wasn't me just being dim-witted).
So I went back to the MPEC, and this time I generated an ephemeris using the Global-rent-a-Scope observatory number for GRAS-12 (E03), set the Epoch to 27 June, and generated an ephemeris with positions ever 10 minutes. This was a bunch of numbers, but I could cut and paste the RA/DEC directly into the GRAS system. There was still some uncertainty. The error estimates of the location of the asteroid were quite large, so even the best ephemeris position could be out, and the asteroid was moving so quickly across the sky (even though it was moving slowly with respect to earth) that the time to position the scope could be a factor in catching the speeding blighter (this is why I chose GRAS-12, with a wide field of view).
But it worked! I was rewarded with two streaks as the tiny asteroid streaked across the sky. Although relatively bright (about magnitude 12), it was moving too fast to build up a decent exposure. I would have liked to get another shot, but to my (and the others using GRAS-12 to image 2011 MD) dissapointment , the clouds rolled over cutting us short. Thanks again to Peter Lake and Pete Poulos of Global-Rent-a-Scope for helping me get these shots.
For a nice animation see Dave Herald's video, and Efrain Morales has some nice images. Other images and animations are here. Stunning animation here.
 |  |
Left image, 2011 MD at 22:46 (local time), when it was moving at 408.78"/min (120 sec exposure with GRAS-12). Right Image, 2011 MD at 23:30 local time, when it was moving at 611.15"/min (120 sec exposure with GRAS-12). The asteroid seems to fade out but its brightness fluctuated probably due to rotation.
Well, some of you might be saying, "so what, all you had to do was put coordinates into a robot telescope, where's the challenge in that?" and there is a degree of truth in that. Mind you, given my inherent fumble-fingeredness, even that can be a challenge. The last time I tried to image a rapidly moving asteroid I neglected to correct for daylight saving time and imaged a patch of empty space. Repeatedly.
But in this case it was more complicated. When I put the MPEC elements into my favourite planetarium programs, SkyMap and Stellarium, the tracks I got back were just rubbish. Peter Lake had actually got some images, and I asked him for help. It turns out that the MPEC generate their ephemeris to a standard epoch, sufficiently far into the future that it messes up with plotting the asteroids track in most planetarium programs (it wasn't me just being dim-witted).
So I went back to the MPEC, and this time I generated an ephemeris using the Global-rent-a-Scope observatory number for GRAS-12 (E03), set the Epoch to 27 June, and generated an ephemeris with positions ever 10 minutes. This was a bunch of numbers, but I could cut and paste the RA/DEC directly into the GRAS system. There was still some uncertainty. The error estimates of the location of the asteroid were quite large, so even the best ephemeris position could be out, and the asteroid was moving so quickly across the sky (even though it was moving slowly with respect to earth) that the time to position the scope could be a factor in catching the speeding blighter (this is why I chose GRAS-12, with a wide field of view).
But it worked! I was rewarded with two streaks as the tiny asteroid streaked across the sky. Although relatively bright (about magnitude 12), it was moving too fast to build up a decent exposure. I would have liked to get another shot, but to my (and the others using GRAS-12 to image 2011 MD) dissapointment , the clouds rolled over cutting us short. Thanks again to Peter Lake and Pete Poulos of Global-Rent-a-Scope for helping me get these shots.
For a nice animation see Dave Herald's video, and Efrain Morales has some nice images. Other images and animations are here. Stunning animation here.
Labels: asteroids, astrophotography, Global Rent-a-Scope
Monday, October 11, 2010
Star GRASing and some Good News!
And now a wonderful bit of news.
As you may know, I buy observing time on the Global-Rent-A-Scope system. Now, you may ask, why would a guy with a 50mm, 4" and 8" telescope, who also hunts comets in the STEREO imager, want to rent telescope time? Don't I have enough telescopes?
You can NEVER have too many telescopes. And the GRAS telescopes allow me to do the kind of deep sky imaging I could never afford to do myself.
Well, the GRAS people have invited me to do a monthly "what's up" blog for them, and I've accepted. The first entry is live here.
http://www.global-rent-a-scope.com/gras-monthly-heads-up/
So if you are a GRAS user, or would like to try out the GRAS system , head on over for some guides for things to look for. Comet 103P Hartley is on the menu this month. I have lots of nice 103p images I must post when I get a spare moment.
As you may know, I buy observing time on the Global-Rent-A-Scope system. Now, you may ask, why would a guy with a 50mm, 4" and 8" telescope, who also hunts comets in the STEREO imager, want to rent telescope time? Don't I have enough telescopes?
You can NEVER have too many telescopes. And the GRAS telescopes allow me to do the kind of deep sky imaging I could never afford to do myself.
Well, the GRAS people have invited me to do a monthly "what's up" blog for them, and I've accepted. The first entry is live here.
http://www.global-rent-a-scope.com/gras-monthly-heads-up/
So if you are a GRAS user, or would like to try out the GRAS system , head on over for some guides for things to look for. Comet 103P Hartley is on the menu this month. I have lots of nice 103p images I must post when I get a spare moment.
Labels: Global Rent-a-Scope
Sunday, June 05, 2011
Crowdsourcing the M51 Supernova (and My Images)
The supernova in M51, Left; The discovery image (from here) on 2 June, Right; Pete Polous's GRAS-07 image of June 3.
My images of M51. Left image: M51 imaged with GRAS-07 on 04-06-11 at 02:
36 UT (300 seconds Luminance). Right image: M51 imaged with GRAS-05 (120 seconds Luminance).Images optimized (Arcsinx) with FITS liberator, then scaled and despeckled with ImageJ.
The supernova is still, bright, but I'll have to do some photometry to see if it is fading.
This is an excellent opportunity to use crowd sourcing as a way of following the supernova. I've already asked the GRAS users to upload there images to the GRAS users page. However, I'd like everyone with images of M51 from May 28 on to submit them to the Flikr group astrometry, which automatically performs astrometry on the images, and will allow us to follow the supernova.
Labels: astrophotography, supernova
Friday, January 13, 2012
In Which I (Fail to) Discover Nibiru: Or Fakery is Flattery
Image purported to be of a large object near 89 Leo, allegedly taken on January 9, 2012 using the GRAS (now iTelescope) scopes. The alleged coordinates are RA 11 34 21 DEC 03 03 35, click on image to embiggen for detail.This image, which is claimed to show the mythical planet Nibiru (or HMO, for Heavy Mass Object), started doing the rounds recently. I became aware of it yesterday, in a Facebook post and briefly pointed out why it had to be a fake.
The purported object is a crescent, yet is supposed to be outside of Earth's orbit, it is impossible for any object outside of Earth's orbit to be a crescent. To be a crescent, the object must be nearly between us and the Sun (try this out with a torch and two tennis balls to confirm it for yourself).
Also, the crescent image has been Photo-shopped in, you can see a difference between the resolution of the object and that of the stars.
But what I hadn't realised is that the image that was Photo-shopped was one of mine.
This image is the result of a stack of 4 x 90 second images of 103P in Andromeda, near the faint he galaxy PGC 71451. Images taken with GRAS 05 on 18-09-2010 stacked and summed on the stars using ImageJ (click to on the image embiggen). The original image is here .
This image is the result of a stack of 4 x 90 second images of 103P in Andromeda, near the faint he galaxy PGC 71451. Images taken with GRAS 05 on 18-09-2010 stacked and summed on the stars using ImageJ (click to on the image embiggen). The original image is here .I paid no more attention to the thread (playing with my nephews and watching Startrek had a higher priority than debunking alleged Niburu sightings). However, while I was sleeping, folks in the US were tracking down the the image.
Francis Walsh noticed that the image didn't look like images of 89 Leo he had taken (you can use wikisky to compare the image to the region around 89 Leo and the image), and Messierhunter noticed the fuzzy object to the left was a comet, a comet he had imaged called 103P, he then tracked down to image, which turned out to be one of mine.
Tbar1984 then created a video pointing out the fake. All while I was peacefully sleeping.
Side by side comparison of my image from 18-09-2010 (right panel) and the image allegedly taken on 09-01-2012 (left panel. Click to embiggen.
Side by side comparison of my image from 18-09-2010 (right panel) and the image allegedly taken on 09-01-2012 (left panel. Click to embiggen.This is a side by side comparison of the two images, the one allegedly taken on 9-01-2012 and mine taken on 18-09-2012. you can see that they are identical. Comet 103P is the killer, comet 103P is not near Leo in 2012, and infact is too dim now (around magnitude 19), to be imaged in all but the most serious iTelescope research scopes, and this image is clearly taken with GRAS05 (the scaling and intensity of the stars is the clue, GRAS 11 now T11, for example, has a very different scaling and photometric response).
It's painful listening to Don Adams try and pretend it is not a fake (especially when he points to what are clearly stars and calls them ships). Folks, you just can't randomly point to a few stars and claim a match, lots of stars will form tetrahedron like alignments, you have to do precise astrometry. What you should do is use Overlay with Difference setting in Photoshop/GIMP to see if the stars align properly.
I have no idea who faked the image by Photo-shopping my original (Don Adams says it came from a "trusted source"), but I suppose I should be flattered that they chose my image as a good example of GRAS imagery. Validates me as an astrophotographer it does.
Apparently rumours are circulating on the web that I have faked MY image, taking the image and blocking out the alleged object. Unfortunately for them, I have the original images and FITS (also, I'm not that good a photoshopper to be able to remove the text from the alleged image without removing the stars the text overlies).
Should be interesting to see what develops over the next few days, but I have no illusions that the Nibiru fans will be dissuaded by mere evidence.
UPDATE: hat tip to Scott Ferguson, who emailed me last night, but I completely ignored the intertubes last night.
Labels: comet, Pseudoscience
Tuesday, February 08, 2011
An Amateur Sees to the Edge of The Universe
Congratulations to Dr. Christian Sasse, who has set the record for the farthest and faintest object an amateur has imaged. Using the newly commissioned global rent-a-scope GRAS-17 telescope, he imaged the quasar J1148+5251 the second most distant object ever observed This quasi stellar object has h a redshift of z=6.41, meaning its light has been traveling for around 13.7 12.8 billion years* to Earth. Read the full story (and see the images) here at the GRAS news site.
(As people may know, I use the global rent-a-scope system and even have a "what's up" blog over there. I'm excited and enthused over what amateurs can do with systems like GRAS)
*BAH, my editing sucks.
(As people may know, I use the global rent-a-scope system and even have a "what's up" blog over there. I'm excited and enthused over what amateurs can do with systems like GRAS)
*BAH, my editing sucks.
Labels: Global Rent-a-Scope
Friday, November 26, 2010
Framing the Image
Chart of Comet 103P near Mel 71 visualized in SkyMap, the rectangle is the approximate size of the global-rent-a-scope G14 instrument's CCD imager field of view (155.8 x 233.7 arc minutes) drawn with SkyMaps CCD frame tool. Click to embiggen.If you are new to astronomical imaging, there are a few tricks that can make your life easier. One of these is being able to work out the orientation of the imaging camera’s (CCD device) field of view. For many objects, we don’t particularly care. The object is centered in the field of view and so long as it is not to big (so that it overflows the imaging space) it will be fine.
But if you want to make a mosaic of an object over a larger area, or if you want to image two interesting objects which aren't close to the center of the FOV, then the orientation of the CCD imaging device is important.
Image of comet 103P Hartley near Mel 71 taken with the global-rent-a-scope G14 instrument, click to embiggen to compare the chart above with the actual image.If the CCD imager is square, like the STEREO spacecraft's H1A imager, no problem, but if the imager is significantly rectangular, like the GRAS 14 instrument at Global Rent a Scope which has a field of view (FOV) of 155.8 x 233.7 arc minutes, or my Philips ToUCam webcam (roughly 20x 10 arc minutes) then you have to be aware of the orientation of the FOV, or your image won't include what you want.
With my web cam it's fairly simple, I can just grab it and rotate it until I have the desired FOV orientation (and since I almost always do planetary imaging with it and have live preview, this is fairly easy to do, except when I was imaging Vesta). With remote scopes it's a bit trial and error, and you may have to do a trial shot to see which way the CCD FOV is oriented. For example, with global-rent-a-scope the imager G14 FOV long axis is oriented North-South, while the G5 imager FOV long axis is oriented East-West (with regard to the star chart orientation, see chart and image above).
Useful information, but what to do with it? Well, all decent planetarium programs can place CCD frame outlines on the maps they have drawn (for example, in SkyMap the CCD frame tool is in the Insert | Camera/CCD frame menu item, in the freeware Cartes du Ciel it's Chart | Lines / Grid | Show Mark). Most will have predefined frames, but will also allow you to draw your own CCD frames. In SkyMap I've created my own frames fo the STEREO H1A imager, my webcam and GRAS12 and GRAS5. For SkyMap you have to convert the arcminute FOV widths in the GRAS website to degrees, minutes and seconds if you are using the GRAS scopes.
All you have to do is get the program to draw the frame for you, and now you can work out what to image.
Well, not quite. There's a few quirks along the way which you have to watch out for. In SkyMap for instance, if you have the screen in RA/Dec mode, the frames will be in the correct orientation for G5, but wrong for G12. To get frames in line for G12, you have to labouriously hand rotate the screen so that the North-South axis runs left-right, then the first frame you put down will have the correct orientation (all subsequent ones will be in the WRONG orientation though, unless you revert to RA/Dec mode, then the subsequent frames follow the first frame orientation ... don't ask me why).
Comet 103P Hartley mosaic showing the nebula NGC 1491 , open cluster King 7, and open clusters NGC 1528 , 1513 and 1545 .Labels: astrophotography, Global Rent-a-Scope
Wednesday, October 13, 2010
Comet 103P in Stellarium, a cautionary tale
Left image, 103P as imaged with the GRAS 14 telescope in New Mexico; Right Image, predicted position of 103P as visualized in Stellarium at the same time.
Stellarium is a pretty handy program. Realistic planetary visualization, customizable, I can run as a planetarium as well as control telescopes, and above all, it's free! You can also add objects to it. However, a reader (Wojtec) has posted a problem with Stellarium's implementation of 103P Hartley.
UPDATE: Reader Dagger stab writes:
If you are using the MPC's Minor Planet & Comet Ephemeris Service as a source, there's an error in your Stellarium data: it should be "orbit_PericenterDistance = 1.058686". (There should be an 8 after the 5.) It's correct in the Celestia script. :)(Thanks RD. Strangely, I used both the JPL horizons data as well a the MPC data, why SkyMap gets it right with the MPC data is a mystery, I will check back)
UPDATED UPDATE: I ended up completely rebuilding the Hartley add-on with fresh MPES data to match SkyMap, and with the rebuilt add-on 103P is within 5' of the CCD position, good performance and about as accurate as SkyMap. I've posted the revised figures on the original post and at the end of this post. The JPL horizons data was older than the MPES data, so it gave wacky results. Makes sense that it was the add-on elements rather than Stellarium being weird.
Wojtec found the Stellarium position was off by over 20 minutes of arc, I've confirmed this, actually, I found a 37 minute of arc discrepancy, and that was using a 103P definition file with the latest MPC parameters. Now this isn't much, for visual location or using binoculars and low power telescopes it will be just fine. But if you are using CCD imaging, then this is a significant discrepancy, if say, you were using the GRAS G14 imager the comet would be significantly displaced (see above images, and the image below which makes it clearer), and with the GRAS G5 imager the comet could be out of frame.
Stellarium location of 103P compared to the SkyMap prediction, and the actual measured position from the G14 CCD image (click to embiggen)I've tired two separate definition files for 103P, and there is still the same discrepancy, in the image to the left I've used the same parameters for SkyMap and Stellarium. So it's not the values. I've also been careful to check that the times were correct (imaging run vs Stellarium prediction) so the apparent differences were not due to timing errors.
Curiously, it only is happening with 103p Hartley (and to some extent 2010 TD54). For Comet Enke, Comet 10P Temple, and Vesta the Stellarium prediction is within 5 minutes of arc of the actual object, which is quite tolerable. It can't be a topocentric vs geocentric problem, the discrepancy for 2010 TD54, which has a huge parallax, was only 18' compare to 103P's 37' difference (and with only a short observation time you would expect a large uncertainty in the 2010 TD54 position).
So, I'm baffled, I'll put up a query at the Stellarium forums [answered rapidly, see above, thanks DS], but for now, just be aware that if you are using Stellarium to guide your telescopic CCD imaging, 103P's position will be off. [Now Fixed, see below]
=======================================
[Hartley]
name = 103P/Hartley
parent = Sun
radius = 24
oblateness = 0.0
halo = true
color = 1.0,1.0,1.0
tex_halo = star16x16.png
tex_map = nomap.png
coord_func = comet_orbit
orbit_TimeAtPericenter = 2455497.76729
orbit_PericenterDistance = 1.058678
orbit_Eccentricity = 0.695113
orbit_ArgOfPericenter = 181.1969
orbit_AscendingNode = 219.7661
orbit_Inclination = 13.6168
lighting = false
albedo = 0.5
orbit_visualization_period = 365.25
===========================================
Labels: comets, stellarium
Saturday, February 19, 2011
The Tarantula Nebula (and FITS Liberator)
Left Image: Tarantula Nebula imaged using GRAS 14 instrument at Global Rent a Scope with 3 x 120 sec Red filter FITS images, 3 x 120 sec Green filter FITS images and 3 x 120 sec Blue filter FITS images. Each series of individual filter runs stacked using in Image J using Z projection of maximum intensity, then stacked and assembled into a RGB composite using ImageJ. Right Image: Single 120 sec RGB filter FITS images stretched using FITS liberator and ArcSinh(x) stretch. Stretched files stacked and assembled into a RGB composite using ImageJ. These are smaller frames of the nebula cropped form the whole image. You really, really need to click on these images and embiggen them (and compare to this APOD image which is 31 hours of exposure).
As people know, I'm a fan of low cost astroimaging. For GRAS remote telescope images, my workhorse is the freeware ImageJ. This works pretty well, especially for stacking and aligning images. However, astronomical images can have a large dynamic range from the very faint to the almost overexposed. How to bring out faint structure without turning the bright sections into glaring blobs.
This is where FITSLiberator comes in, it's a freeware app (also there are photoshop plugins), which makes it very easy to adjust the dynamic range of your images for later assembly in other image processing programs (You can do something similar in ImageJ but it's not as easy). As you can see above, with FITS liberator I was able to adjust the dynamic range of my Tarantula Nebula images to almost match the brightness of the multi-stacked images, without the central regions getting overexposed or the background being over-coloured.
Obviously my Tarantula Nebula won't win the astrophotography contest, and I still have a lot to learn, but I'm going to get a lot more out of my images now.
The FITS Liberator website comes with links to a whole range of Hubble raw images, and step by step instructions so you can create your own version of classic Hubble pictures. The PDF user manual is here.
Whole frame of the Trantual nebula and bits of the Large Magelanic cloud taken with GRAS-14. Click to embiggen (warning 2 meg of image)Labels: astrophotography, FITSLiberator, gimp, Global Rent-a-Scope
Sunday, September 05, 2010
Comet 103P/Hartley via GRAS
Left image: 120 second image taken with GRAS 05, clear filter. Right image: Stack of 4 120 sec images.
So it's been pelting down with rain here. In Australia, when a drought breaks, it BREAKS. With with all the flooding, people hit by lightning, not to mention the 70 Km/hr winds removing the garden furniture, astronomy is off the menu, so to speak. Even the Global rent-a-scope facility up north has been hit by really bad weather.
However, the global rent-a-scope network has scopes over in New Mexico, USA. So while the Australian network is under cloud, now was a good time to try and see if I could image 103P/Hartley. The great thing about the US scopes is that it's deep night over there while it's daytime here, so I don't have to wait up until the wee hours for the comet to rise.
I imaged the comet using the medium deep scope GRAS-05. I went for 120 second exposures because of my previous experience with the scopes. I took 4 concurrent exposures. For the images above I took the pre-calibrated files the system sends back. The first is a single file with brightness and contrast adjusted using ImageJ. In the second, I manually aligned the comet images in ImageJ (using the translate function, a right pain let me tell you), then added them with the image calculator function, then messed around a little with the contrast.
The result isn't too bad, the stacked image shows a decent coma and little tail. People aren't getting much better structure with longer exposures and more stacking. Here's a false colour animation I made from those 4 images (the bright objects to the right and below are hot pixel artefacts I can't get rid of). I'll certainly be keeping a remote eye on this comet as it evolves.
Labels: Global Rent-a-Scope
Thursday, November 25, 2010
Comet 103P/Hartley near Mel 71
Comet 103P Hartley near the open cluster Mel 71 on November 23, The image immediate left is a cropped shot from Global Rent a Scope GRAS-05 (click to embiggen).Despite strong Moonlight I think it came out rather well.
The image is a stack of 3 x 30 second images with dark frame subtraction stacked in Image J using Z projection of maximum intensity and a lot of contrast fiddling. I still can't work out how to subtract flatfields correctly though.
This is a widefield image of the same area in GRAS 14. This is a colour series stacked in Image J using its colour series module.The colour is pretty rubbish (but hey, I'm red-green colour blind), but you can clearly see the comet near Mel 71, Mel 72 off on the right hand side of the image and NGC2423 off to the left. You definitely need to click to embiggen this one.
I have no idea why the colour is so weird here, my previous colour shots have been fine. Well, I have the originals to play around with.
I still have a whole bunch of 103P images to post, and lots of 103P news as well (and 2010 V1 image links). The comet is going to be in spectacular territory in the next few days, but strong Moonlight is a problem.
Labels: astrophotography, comets, Global Rent-a-Scope
Tuesday, November 23, 2010
Comet 43P Harrington near NGC 4094
Comet 43P Harrington imaged near NGC 4094 using Global-rent-a-scope GRAS-05 on 19 November.This was going to be a bit of a challenge, 43P is a dim, 14.5 magnitude comet. At astronomical twilight it was only 25 degrees above the horizon, just within range of the GRAS scopes and clearing away from the horizon murk.
The image is a stack of 2 x 90 second frames (after dark frame correction), converted to a single image using Z projection of MAX intensity. It should have been 3 but the scope lost tracking on the last image.
Still, I think it came out rather well, more images to stack would have been better, but the time frame was tight.The image to the left is the SkyMap chart of the same field
Labels: astrophotography, comets, Global Rent-a-Scope
Thursday, September 22, 2011
Comet C/2009 P1 Garrad, September 20 and 22
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Left Image: Comet 2009 P1 Garrad on 20/9/2011. Right Image: Comet Garrad on the 22/09/11. Click to embiggen. Comet C/2009 P1 Garrad imaged using the Global-Rent-a-Scope GRAS-05 instrument.
The left image was done from 120sec luminance RGB filers at 1x binning, the right luminance 120 sec 2x binning and RGB 60 secs with 2x binning. Images stretched with FITS-Liberator, aligned and cropped in ImageJ then luminance and RGB channels assembled in the GIMP, with a little contrast enhancement.
Not as good as Rolando Ligustri's image using the same exposure and binning on the GRAS-11 instrument. I still have a lot to learn about colour image processing.
Labels: astrophotography, comet, Global Rent-a-Scope
Monday, December 13, 2010
Asteroid 596 Scheila has a cometary outburst.
Over at the Global-Rent-a-scope news blog, asteroid 596 Scheila has been reported to have had a cometary-like outburst, and GRAS observers have confirmed this. See more images and the story at the Remanzacco Observatory blog, from GRAS observers Ernesto Guido and Giovanni Sostero (most recent image here), and this nice image from Rolando Ligustri here. The asteroid is enveloped in a spiral cloud or tail, I'll try and keep you updated as the outburst evolves.
Friday, June 03, 2011
Supernova in M51
Image via Digital Sky via Stuarts tweetFrench amateurs have reported a supernova in M51 (2 June 2011 at 00:52 UTC). Details (in French) and images here.
It's a Type II supernova, more details here. Sadly, all the GRAS telescopes are offline at the moment (curse you daylight).
Update: The Sun has set in Spain and Pete Poulous Sends this image of M51 taken with GRAS-07 using a a 300 sec luminance exposure.
Labels: supernova
Monday, September 19, 2011
Comet C/20009 P1 Garrad Septmeber 18
Comet C/2009 P1 Garrad imaged using the GRAS-05 instrument (compare with this June 29 image from GRAS-05). Click to embiggen.1 x 120 sec red, green and blue filter exposures stretched with FITS liberator then assembled into an RGB composite using the GIMP (I usually use ImageJ, but I'm trying a different approach this time). This is illustrated with the image below:
My image from August 26 taken with the Global-Rent-a-Scope G-14 instrument (1 x 120 sec red, green and blue filter exposures stretched with FITS liberator then assembled into an RGB composite using the GIMP, click to embiggen) compare this with the same image stretched with FITS liberator then assembled into an RGB composite using ImageJ.Labels: astrophotography, comet, Global Rent-a-Scope
Friday, October 29, 2010
Asteroid 2003 UV11 zips past tonight
The Earth and Moon as seen from asteroid 2003 UV11 at closest approach, simulated in Celestia.Asteroid 2003 UV11 will flash through our skies tonight and tomorrow morning. Unlike 2010 TD54, 2003 UV11 will be relatively sedate and bright (magnitude 11.9 at its brightest).
Australian observers are best positioned to see the asteroid at its brightest (looks at cloud outside, and GRAS G14 is offline [sob], no back online now), but the relatively low distance above the horizon (32 degrees from Adelaide at the time of brightest approach) will make it a bit hard to follow. You will need a decent telescope to see the asteroid, binoculars won’t pick it up.
I have made spotters maps, which you can see over at my GRAS blog. To make your own, you can download orbital elements for this asteroid from the Minor Planet Ephemeris Center, or hand enter them from here:
Epoch 2010 July 23.0 TT = JDT 2455400.5 MPC
M 278.16307 (2000.0) P Q
n 0.56393601 Peri. 124.79517 -0.91668496 -0.39581712 T = 2455545.61740 JDT
a 1.4509401 Node 31.98952 +0.32434442 -0.81726321 q = 0.3440439
e 0.7628821 Incl. 5.95175 +0.23342962 -0.41881936 Earth MOID = 0.00748 AU
P 1.75 H 19.4 G 0.15 U 2
Location of 2003 UV11 in the sky above Adelaide, at 10:00 ACDST visualized in Stellarium (click to embiggen)As usual I have made a Stellarium file and a Celestia file for the asteroid. As usual, add the Stellarium elements to the end of the system.ini file and save the Celestia file in extras. The Stellarium file makes the asteroid brighter than it should be, for easy spotting, to be more realistic set the radius to 0.3.
[2003UV11]
name = 2003UV11
parent = Sun
radius = 3
oblateness = 0.0
albedo = 0.15
lighting = true
orbit_visualization_period = 1325.46
halo = true
color = 1.0,1.0,1.0
tex_halo = star16x16.png
tex_map = nomap.png
coord_func = comet_orbit
orbit_Epoch = 2455400.5
orbit_TimeAtPericenter = 2455545.61740
orbit_MeanAnomaly = 278.16307
orbit_SemiMajorAxis = 1.4509401
orbit_Eccentricity = 0.7628821
orbit_ArgOfPericenter = 124.79517
orbit_AscendingNode = 31.98952
orbit_Inclination = 5.95175
======================================2003UV11.ssc=======================================
"2003 UV11" "Sol"
{
Class "asteroid"
Mesh "ky26.cmod"
Texture "asteroid.jpg"
Radius 0.3 # maximum semi-axis
MeshCenter [ -0.000718 -0.000099 0.000556 ]
InfoURL "http://en.wikipedia.org/wiki/2003_UV11"
EllipticalOrbit
{
Epoch 2455400.5 # Epoch 2010 July 23.0
Period 1.75
SemiMajorAxis 1.4509401
Eccentricity 0.7628821
Inclination 5.95175
AscendingNode 31.98952
ArgOfPericenter 124.79517
MeanAnomaly 278.16307
}
RotationPeriod 0.178 #made up
Albedo 0.15 #made up
}
=========================================================================================
Labels: asteroids, astrophotography
Friday, October 15, 2010
Comet 103P/Hartley near NGC 1491
Comet 103P Hartley is getting very bright now (for astronomical values of "bright", it's just a dim fuzzy dot to the unaided eye).Last night I got some images of the comet near the nebula NGC 1491 and the Open cluster King 7. To the immediate left is a cropped wide-field shot from Global Rent a Scope GRAS 14 (stack of 3 black and white images at 60 seconds each). Click to embiggen (it's worth it). Due to stacking the images on the stars the comet is smeared.
This image is an RGB composed image of single 90 second RBG frames taken with GRAS 05. Again click to embiggen. I used the RGB composer module of Image J, I think I'm doing it wrong, maybe I should read the manual :-0I have have been taking images of 103P for nearly 2 weeks. I really should post them.
Labels: astrophotography, comets, Global Rent-a-Scope
Saturday, October 15, 2011
Waiting for Comet Elenin
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Left Panel: Image from the STEREO H2A imager on 9 October showing Earth (bright object with long artefact spikes to the left of Centre), comet 45P/Honda-Mrkos-Pajdušáková (near centre with visible tail) and Neptune (far right), predicted position of Elenin shown as well. click to embiggen.
Right Panel: Image taken of predicted position of Elenin on 12 October. Image composed of a stack of 4 x 120 second luminance exposures in the Global-Rent-a-Scope GRAS-05 instrument (stacked in ImageJ), tracking on the predicted position of Elenin. Images taken between 20-5 minutes before astronomical twilight, but still lots of interfering Moonlight. No object appears near Elenin's predicted position (image centre), stars down to magnitude 14 visible, the spikes are imager artefacts (click to embiggen).
Well, September 27, when comet C/2010 X1 Elenin, Earth and the Sun were aligned, has come and gone without massive earthquakes (or any earthquakes at all really, there were no quakes of M 6+ around then), the Pacific Ring of Fire did not burst with with volcanic eruptions, andwell, not much of interest happened really. Just like we astronomers predicted.
Now we are waiting for Elenin's closest approach to Earth, on October 16 12:20 UT (that's about 11:20 pm in Australian Eastern daylight saving time. Elenin has been high enough above the morning horizon for scopes to pick up for a couple of days yet, however, bright Moonlight makes picking up dim objects not far above the horizon difficult.
Amateurs have been scanning the sky for any sign of the remnants of Elenin after it's disintegration, but so far no confirmed sightings. A couple of very experienced observers have reported a sighting of an object at magnitude 9-10, but many other experienced observers have found nothing down to much lower limiting magnitudes (see here and here). My images, taken with Global-Rent-a-Scope GRAS-05 instrument above, don't show anything and a magnitude 10 object should have shown up with stacking.
The last reported sighting of Elenin in STEREO was by Comet Al, in images from H2A on October 9. This was at the limit of detection, so this implies the comet remnants are around magnitude 10.5 or 11, pretty dim. My image from the STEREO H2A imager is above. I can't see anything where Elenin should be, but comet 45P/Honda-Mrkos-Pajdušákováand its tail are clearly visible, as is Neptune, so any remnant must be much dimmer than that. You can see an animation showing 45P's tail twisting in the solar wind here (warning 2 meg AVI file).
If comet Elenin hadn't disintegrated, it should have been between magnitude 6.5-7.5 by now, easily visible even under the conditions we have at the moment.
That hasn't stopped the conspiracy people though, after Elenin failed to do anything doomsdayish during it's alignment with the earth and Sun, they have no moved on to worrying about Elenin's "debris field" doing something bad at the time of closest approach. However, the remnants of Elenin will be nowhere near Earth.
So, astronomers will continue to observe , looking for Elenin. As the Moonlight wanes and the comet gets higher above the horizon, we may be able to pick up some of the debris of this comet.
Labels: comet, comets, Global Rent-a-Scope
Sunday, October 23, 2011
Comet C/2010 X1 Remnants Recovered.
Where comet Elenin should have been, the faint debris doesn't register of this stack of 5 x 2 minute exposures taken with GRAS-05. After intense searching for the remnants of comet C/2010 X1 Elenin, which began to disintegrate back in August, there finally appears to be confirmed images of a debris field (that the Moon has waned somewhat probably helps too) .
Images from Rolando Ligustri show a nebulosity stretching along the predicted position of Elenin. Similar nebulosities at the predicted location of Elenin, found at different times (ie the debris field is moving along Elenin's orbital path) are found in these images from Leonid Elein, Michael Jäger , Jakub Cerny and Juanjo González Díaz.
The remnants are very faint, for example Rolando needed to stack six x five minute exposures from a sensitive CCD camera (GRAS-20) together to show the dim cloud of material. Scientifically, this is very interesting, we have few examples where we can follow the debris trail of a disintegrated comet. How long amateurs can follow this faint patch of dust for is unknown, but it will probably continue to fade rapidly. Update: Rolando's latest image suggests that the remnants are fading fast.
The only people realy disappointed by this is the Doom-sayers, who will no loger be able to terrify people with laes of the scary comet Elenin.
Labels: astrophotography, comet, comets, Elenin, Global Rent-a-Scope
Wednesday, October 27, 2010
Comet 103P/Hartley near M35
Mosaic of images showing Comet 103P Hartley near M35 (top image near middle), NCGC 2158 (just above M35), CR 89 (hard to see, to the left of the comet) and 1 Geminorum (brightest star). Click to embiggen for open cluster goodness.The comet appears as multiple images as this is a stack of 3 x 60 second exposures in Global Rent a Scope GRAS 14 and stacked in Image J using Z projection of maximum intensity and a bit of contrast fiddling. Two series of exposures was made, one on the comet and one on M35, the composed images were made into a mosaic using the GIMP, with layers, and using a little bit of rotation to get the star images aligned.
The images are a bit rubbish as a) the Moon was pretty close and b) the cloud that I thought had gone away hadn't (the streamers in the comet image isn't a nebula). Later I'll try and match the background better, maybe eliminate an image from the stack to see if can get it better.
UPDATE: Rolando Ligustri does it much much better, his stunning image is here.
Chart of the region identifying objects in the above image, the rectangles show the field of view of the GRAS 14 imager (again, click to embiggen).Labels: astrophotography, comets, Global Rent-a-Scope
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